liquid for me. i use 6-8ml/gal. week 5: coco a/b, drip clean, bud xl, top booster........ week 6: coco a/b, *drip clean, bud xl....... week 7: coco a/b, *drip clean, bud xl, hydroplex......... week 8-whenever is the same til i flush. i used to use shooting powder but i dont really care for it